Importing Preexisting Terrain into SketchUp (and Geolocate a Model)

Does the terrain that you want to model exist somewhere outside your imagination and in digital form? Hurrah! You can just import it!

Well, sort of. Also, after you import terrain, you usually need to edit it. At minimum, you likely need to clean up the imported data by reducing the number of faces to improve your model’s performance, tracing contour lines, or a few other tasks covered in Editing and Fine-Tuning Terrain. But for now, enough of the sour details.

This section focuses on the happy, easy part of importing terrain. In SketchUp, you can bring terrain into your model in the following ways:

Grab a location from Trimble. In SketchUp Pro, this method is the easiest way to import terrain, and the steps to do it appear later in this section. Importing terrian is not available with SketchUp Make or my.SketchUp.

Import contour lines. If your contour lines are a raster image file, you can trace the contour lines in SketchUp. If you can import actual geometry, you just need to turn the contour lines into a TIN (triangulated irregular network) using the From Contours tool, as explained in Creating Terrain from Scratch.

Tip: If your contours are a vector image or a .dwg file (which is a CAD file format that only SketchUp Pro supports), SketchUp imports your contour lines as geometry, rather than an image that you need to trace. For performance reasons, simplify your contours in your image editor or CAD program as much as possible before importing the contour lines into SketchUp.

Import a polygon mesh. A mesh comes from a CAD program such as AutoCAD. A polygon mesh is like a TIN but contains faces with more than three vertices. That is, a mesh can contain polygons, not just triangles like a TIN, and you can use SketchUp’s Sandbox tools to edit the mesh.

For all the details on what types of files you can import into SketchUp (such as image files or CAD files) and how to import a file with your terrain data, see Using SketchUp Data with Other Modeling Programs or Tools. Then check out the aforementioned article about editing terrain. For details about grabbing terrain from Trimble via SketchUp’s built-in tools, keep reading.

In SketchUp, when you grab terrain from Trimble, you’re technically importing a geolocation snapshot into your SketchUp file. A geolocation snapshot includes the following elements:

The geographic coordinates of your selected location: These coordinates aren’t absolutely necessary for modeling terrain, but if you import this data, SketchUp can use it to create realistic shadow studies or display your model in Google Earth. See Communicating Your Designs for details.

In the Add Location window that appears, type an address or intersection where your desired terrain is located.

Click the Search button, and an aerial view of your location appears in the window. In the figure, you see the results for the Boulder Public Library, or more specifically, its address at 1001 Arapahoe Ave., Boulder, CO 80302.

(Optional) To see all the terrain that you want to import, use the zoom controls on the left, or scroll your mouse wheel to zoom in or out.

Click Select Region in the upper-right. An selection box becomes highlighted in the Add Location window. The highlighted area represents the area of terrain that you’ll import into your model.

Click and drag a corner of the selection box so that the selection highlights only the terrain you need. In the following figure, you see how the aerial view of the library looks after zooming in and adjusting the selection box to highlight only the library building.

Tip: The edges and faces in a terrain add up pretty quickly. The more edges and faces your model has, the more processing power SketchUp needs to render your model on-screen. When you select only the terrain you need, you don’t have unnecessary edges and faces bogging down your model.

Click the Grab button in the upper right. By default, a 2D image of the selected area appears in your model, as shown in the following figure. However, you can toggle between 2D and 3D and change the view to show or hide the Snapshot. Toggling Terrain Visibility explains all your options.

Note: After you geolocate a model by importing terrain, the north angle changes slightly. When you export a model to a format such as .kmz, this small rotation improves the accuracy of tracing the image as the file is converted from Cartesian coordinates to UTM or Mercator.